Method of manufacturing a downhole electrical cable

Abstract

A method of manufacturing a downhole electrical cable is described. The method comprises arranging an elongate member adjacent to a flat elongate sheet of material, where the length of the elongate member is greater than the length of the flat elongate sheet. The elongate sheet is then formed into a cylindrical shape around the elongate member, and the adjacent longitudinal edges of the cylindrical shape are joined, preferably by seam welding, to form the elongate sheet into a tube with an end of the elongate member adjacent each end of the -tube. Thereafter, an elongate conductor is connected to one end of the elongate member, and the other end of the elongate member is pulled to draw the elongate conductor through the tube until the elongate member is removed from the tube and the elongate conductor is located within the tube. At this final point in the method, an end of the elongate conductor is adjacent each end of the tube.

I claim: 
     
       1. A method of manufacturing a downhole electrical cable, the method comprising arranging an elongate member adjacent to a flat elongate sheet of material, the length of the elongate member being greater than the length of the flat elongate sheet; forming the elongate sheet into a cylindrical shape around the elongate member; joining the adjacent longitudinal edges of the cylindrical shape to form the elongate sheet into a tube with an end of the elongate member adjacent each end of the tube; coupling an elongate conductor to one end of the elongate member; and pulling the other end of the elongate member to draw the elongate conductor through the tube until the elongate member is removed from the tube and the elongate conductor is located within the tube, an end of the elongate conductor being adjacent each end of the tube. 
     
     
       2. A method of manufacturing downhole electrical cable according to claim 1, wherein when the elongate sheet is formed into the tube, an end of the elongate member protrudes from each end of the tube. 
     
     
       3. A method of manufacturing downhole electrical cable according to claim 1, wherein the adjacent longitudinal edges of the cylindrical shape are joined by seam welding the edges together. 
     
     
       4. A method of manufacturing downhole electrical cable according to claim 1, wherein the elongate conductor further comprises a conductor element and an external coaxial electrically insulating means. 
     
     
       5. A method of manufacturing downhole electrical cable according to claim 1, wherein a fluid barrier device is interposed between the elongate conductor and the tube. 
     
     
       6. A method of manufacturing downhole electrical cable according to claim 5, wherein the fluid barrier device is a curable material. 
     
     
       7. A method of manufacturing downhole electrical cable according to claim 6, wherein the curable material is inserted into the annulus between the elongate conductor and the tube, and thereafter the curable member is cured. 
     
     
       8. A method of manufacturing downhole electrical cable according to claim 5, wherein the fluid barrier device is a mechanical device. 
     
     
       9. A method of manufacturing downhole electrical cable according to claim 8, wherein the mechanical device forms a seal between the elongate conductor and the tube. 
     
     
       10. A method of manufacturing downhole electrical cable according to claim 5, wherein the elongate conductor is locked with respect to the tube by a locking device. 
     
     
       11. A method of manufacturing downhole electrical cable according to claim 10, wherein the fluid barrier device is the locking device.